cnt LAMP WORKS 
OF GENERAL ELECTRIC CO. 


ENGINEERING 
DEPARTMENT 


‘4 
: Bulletin 41-D 
Jone 1, 1928 Second Edition 


Hlumination 
Design Data 


for 
Industrial and Commercial 
Interiors 


By 
WARD HARRISON AND C. E. WEITZ 





This bulletin presents a method of illumination design 
which has become the standard for illuminating engineering 
work. Through its use tedious calculations of the ‘‘point by 
point’ method are avoided; the time required is reduced to a 
few minutes; and even those not experienced in lighting design, 
by following carefully the steps as outlined, can at once apply 
these data with confidence. 


The method of design is known as the “lumen method.” 
It has the decided advantage that the technical considerations 
which are important as influencing the result and which 
require the experienced judgment of the engineer, have been 
taken into account in the preparation of the charts and tables 
and therefore automatically receive due allowance in the 
lighting design. The data apply primarily to interiors 
where standard types of reflecting equipment are used to 
obtain general lighting of substantially uniform level. 


The experienced engineer may temper rule-of-thumb 
methods with Judgment and secure satisfactory resulis, but, 
in the final analysis, all short-cut or recipe methods which are 
effective must be governed by principles as given in this ~ 
bulletin. For the student, the essence of illuminating 
engineering will be found in a studied analysis of the factors 
which make up the tables in their present form. 


Illumimation Design Data 
for 
Industrial and Commercial 


Interiors 


A Handbook for 
Lighting Specialists, Electrical Contractors and 
Dealers, Engineers, Architects, Students, 
and Instructors 


ENGINEERING DEPARTMENT 
NATIONAL LAMP WORKS 
of General Electric Co. 





Sheet Metal Stamping — 20 Foot-Candles 


The difference between good illumination which cheers the mind and comforts 
the senses, and poor lighting with its gloom and glare, obviously is nothing 
more than the difference in results as produced by modern equipment—reflectors 
and lamps—properly installed, and the results produced by mediocre equipment 
installed without regard or knowledge of principles and good practice. 


9 


< 







MeNOORORDENNOHDODOENURDOONNONDAUAONPOODONONORNOONOGHCOOUOUEDOOONGOSEROSUNCEEOONGHOOOONGOROODUGUCHOOOOCODOOCEEEODEPCOEDOONOUONAUGEOEOOONOUCEOLAONOSOOONEOGUOUNELDOONOHCEOHOEECESOOOOCEDOONTORDORaSoaOoeN DeEoORt 


ILLUMINATION DESIGN DATA | 


3 
| for 
i Industrial and Commercial Interiors 


Page 
1. Location of Outlets—Adequate Wiring 4-5 
Spacing-Mounting Height Tables.......... 6-7 
eyDICalcLAVOULS womemar. eminent 8-9 
Wiring: @apacity-per_ Outletsa,) rere acne 10 
Wire size for Branch Circuits), ......5.... 11 
2. Foot-Candles Required.............. 12 
Recommended Values...... PRE ee 13-18 
3. Room Efficiency and Reflector Char- 
ACTELISLICS Heese ee ie he ee 19-21 
Room ndexs) able er eee ee Seer: 22-23 
(Zoemcients ots tiizaliOn ss eee ee 24-29 
Speciale Units reve ote re, ne eee Oe ele to 28-31 
4. Lamp Size—Lumen Output Required 
Table of Computed Values............... 32-33 
Formulasfor;Computation = «en. oe 34. 
List of Equipment Manufacturers...........:...... 35-36 


1. Location of Outlets—Adequate Wiring 


Lighting standards which we accept today are not only on a 
better level than those of a few years ago, but studies in light 
and vision point to even higher standards, which will unquestionably 
be used in the future. 


The wiring plan is the foundation of the lighting system and 
indeed, is the step that should be given the most careful attention. 
Because the cost of relighting is made up so largely of wiring costs, 
it is far more economical, in planning a lighting installation, to 
provide wiring adequate for future as well as present needs. 


When once outlets are properly installed as regards both spacing 
and size of wire, a change in type of reflector or in size of lamp, 
may be made without undue complication; but where the spacing 
of outlets is too great or the wiring inadequate, satisfactory results 
can never be obtained without extensive alteration. 


KOK KOK OK OX 


The number of outlets to provide for any given area is 
determined by the maximum allowable spacing between lighting 
units and is in turn regulated by their height above the floor. The 
relation between height and spacing is based on the distribution of 
light to procure a reasonably uniform level of illumination on the 
working plane. Careful analysis of the accompanying drawings 
will illustrate the importance of this principle. 


Strictly speaking, the spacing for uniform illumination on the 
work depends upon the height of the light source above the surface 
to be illuminated, but since most work surfaces are from 2% to 3% 
feet above the floor, the spacing may for practical purposes be 
considered a function of the mounting height of lamps above the 
floor. In general, a spacing in feet which does not substantially 
exceed this mounting height will result in reasonably uniform 
illumination. See Tables 1 and 2. 


When lighting units are mounted as high as the ceiling or roof 
trusses permit, larger and more efficient lamps may be used, while 
fewer units—to buy, to install, and to maintain—will be necessary. 
The ceiling height, or rather the height which units may be mounted 
clear of obstructions, therefore dictates the maximum permissible 
spacing. 

4 





LOCATION OF OUTLETS—ADEQUATE WIRING | 


0 fect 





Fig. 1—Units spaced too far apart for their height furnish very uneven 

illumination, in this case a 4 to 1 variation, and work positions midway 

between units will be inadequately lighted; harsh shadows will also result. 

The remedy is to mount the units higher, or if that is impossible, to space 
them closer as shown in Fig. 2. 





Fig. 2—It will be noted that if the permissible ratio between spacing and 

mounting height is not exceeded, uniform illumination will be produced. 

Note also the overlapping of light which serves to eliminate shadows as 
the units are brought closer together. 


With a light source only 8 feet above the floor one unit would 
be required for each 55 square feet to give reasonably uniform 
coverage; for a 10-foot height a unit for each 125 square feet; 
15-foot height, 325 square feet; 20-foot height, 650 square feet, etc. 


The arrangement of bays, columns, positions of work, however, 
often suggests a closer spacing to conform to a symmetrical layout, 
or a more favorable location with respect to work positions where 
these are known in advance. 


Specific data and typical layouts follow. 
5 














LOCATION OF OUTLETS—ADEQUATE WIRING 


Spacing of Outlets 

The location of outlets is determined by the structural features 
of the interior—in fact in many cases, particularly in new buildings, 
the wiring is installed even before the type of lighting unit is 
decided upon. The ceiling height therefore automatically regulates 
the maximum permissible spacing, assuming the units are mounted 
as high as possible. 











The layout of lighting outlets for a large industrial building, indicating the 
application of data in the table below. The 13-foot clearance allows a spacing 




















of 13 feet. For a symmetrical layout in the bays a 10-foot spacing is adopted. 
TABLE 1—SPACING OF OUTLETS 
Ceiling Spacing Between Outlets =p a Oe ide Approximate 
Height Area per 
(Or Height in Maximum Aisles or Desks, Work- Outlet 
the Clear) Usual (For Units at | Storage Next | benches, etc., (At Usual 
Ceiling) to Wall Against Wall Spacings) 
(C) (D) (D) (A) (B) 
(Feet) (Feet) Not more than* Not more than*| (Square Feet) 
8 i 7% Usa 3 50-60 
9 8 8 y 3 60-70 
10 9 9 3% 70-85 
ll 10 1014 ae 3% 85-100 
12 10-12 12 314-4 100-150 
half ee 
13 10-12 13 34%-4% 100-150 
14 10-13 15 actual 4-5 100-170 
9 GE steve 4-5 100-170 
-13 19 . 4-6 100-170 
18 10-20 21 ee 4-6 100-400 
20 18-24 24. between 5-7 300-500 
22 20-25 aT 5-7 400-600 
24 20-30 30 units 6-8 400-900 
26 25-30 ats 8-9 600-900 
30 and up 25-30 40 8-10 600-900 




















* Where it is definitely known that some form of indirect lighting will be used, the maximum 
spacing between outlets may be increased about two feet, and the distance from the outside 
outlets to the wall may be increased by one foot. 


6 


LOCATION OF OUTLETS—ADEQUATE WIRING 
Mounting Height of Lighting Units 
When units are spaced less than the maximum permissible 
distance, they may be dropped from the ceiling for reasons of 
appearance, ease of cleaning, etc., but in no case should they 
be dropped below the minimum value shown in column (H) for 
a given spacing. 











bE 


For a 10-foot spacing the units might be dropped to 10 feet above the floor as 
shown by the dotted outline of a reflector at height H. They are, however, 
mounted on the trusses 12 feet to minimize glare. 


TABLE 2—MOUNTING HEIGHT OF LIGHTING UNITS 


SEMI-INDIRECT 
AND INDIRECT 





DIRECT LIGHTING UNITS 








LIGHTING 
: Recom- 
Distance mended 
ose of Units Desirable Mounting Desirable Mounting Actual | Suspension 
Reticaen, from eight in Height in | pease Length 
etween | Floor Industrial Interiors Commercial Interiors etween | (Top of 
Units | Not Less Units Bowllte 
Than Ceiling) 
(D) (AH) (R) (R) (D) (S) 
F F : F F 
; ee ee 12 feet above floor if a : i 
possible—to avoid ? 
8 | 8% | glare, and still be Ee 
9 9 Es hires hatren The actual hanging 9 1-3 
10 10 stepladder for poe eed is 10 144-3 
11 10% cleaning. g I gely 11 2-3 
12 11 by panera ePponts 12 2-3 
I ance, but particu- va 
a 1274 : larly in offices and or: aEP 
15 be mounted much | minimum values Oe 
20 16 more than 12 feet | shown in Column 20 4-5 
22 18 it is usually desir- | F{ should not be 22 4-5 
24 20 able to mount the | yjolated. 24 4-6 
26 21 units at ceiling or %6 A-6 
28 929 on roof trusses. 28 oy) 
5-7 











LOCATION OF OUTLETS—ADEQUATE WIRING | 





Layouts Suggested for Symmetrical Spacing 


Where interiors are divided by columns or ceiling beams into 
bays, it is usually desirable because of appearance to locate the 
outlets symmetrically with respect to these structural sections. 
The typical layouts and notes which follow suggest various 


arrangements of units with respect to bays. 





Layout A 
Four Units per Bay—This is the 
most common system for the square 
bay of usual dimensions. 


Layout B 
Four-Two System—This is equiva- 
lent to three units per bay and is an 
alternative to four per bay where 
permissible spacing allows. 





Layout C 
Two Units per Bay—Usually appli- 
cable only in narrow bays where the 
width is less than two-thirds the 


length. 





Layout E 


Staggered System—A recourse 
where one unit per bay is unsatis- 
factory and where four per bay is 
unnecessary. Less favorable appear- 
ance, and certain areas near walls 
may be inadequately lighted. Often 
expensive to wire. 


Layout D 
One Unit per Bay—A very common 
practice, but satisfactory only where 
bay size is no greater than the maxi- 
mum permissible spacing—an unusual 
condition. 





Layout F 


Interspaced System—A pplicable in 
rectangular bays where one unit per 
bay would exceed the permissible 
spacing in one direction, and where 
center row will not interfere with 
future structural arrangements, such 
as added office partitions. 


LOCATION OF OUTLETS—ADEQUATE WIRING 


Layouts for Special Applications 

The adoption of well-designed general lighting systems elimi- 
nates the need for a great many “ingenious” lighting devices. 
However, in certain locations, particularly in manufacturing opera- 
tions, requiring high machines or peculiar machine grouping, 
special attention must be given to the layout of the general lighting 
or to the use of units supplementary to the general system. 








Warping Machines -Textile Mill Group Lighting 





Units are arranged with respect to 
machine groups to give better direction of 
light and to avoid high machines cutting 
off light where needed. Usually encoun- 
tered in standardized industries such as 
textile, paint, paper, and printing. 





Craneways 


Hts = 








Mount units on truss chords or hang 
conduit from messenger cable. Stagger 
units as shown to avoid traveling crane 
blocking off light from all units in the 
row parallel to the crane as it travels along. 








mee 


Angle Units 
In erecting shops in high bays, angle 
units along the walls—20 feet high—will 
provide additional light for vertical surfaces. 
Similarly, large high machines or special 
operations frequently require supplementary 
units, mounted perhaps on columns close by- 















































Bench Lighting 


If the general lighting system is well 
planned, special bench lighting is unneces- 
sary except where there is fine bench work 
requiring much higher illumination than is 
provided throughout the room. 


TTT 


Special Purpose Units 


Some cases require special study because 
of peculiar requirements. This illustrates 
the use of special units to spread a high 
intensity band of light on the vertical 
surfaces of an automobile body for finishing 
and inspecting. 





9 





“LOCATION OF OUTLETS—ADEQUATE WIRING 





Adequate-Wiring Data 







WI5 volts 
Circuit 5 


The Underwriters’ Code merely 
specifies wiring conditions with regard to 
fire hazard without giving consideration 
to the economy of operation. The size of 
wire for a lighting installation may conform 
strictly to the code and at the same time 
the circuits be of such length to cause 
excessive voltage drop. Inadequate 
wiring is directly responsible for the 
avoidable waste of electrical energy in 
overloaded circuits and results in low 
efficiency of lamps and _ unsatisfactory 
lighting conditions. 


15 volts 
Circuit 6 




































































7 volts 

At panel box 

Wattage Capacity per Outlet—Number of Outlets per Circuit—In 
order that a higher wattage lamp may be used in each outlet at any future date 
without necessitating a rearrangement of circuits, it is recommended that the 
capacity per outlet as given in Table 3 be allowed, and, in general, the number 
of outlets per circuit as follows: where the capacity is 300 watts or less, not 
more than 8 per circuit; where 300 to 750 watts per outlet is specified, not more 
than 4 per circuit; where more than 800 watts per outlet is specified, not over 
two!'should be on each circuit. 


TABLE 3 
ARCHITECTS’ AND ELECTRICAL CONTRACTORS’ WIRING GUIDE 


(See Table 4 for Wire Size) 


CLASS A CLASS B CLASS C CLASS D 














Actual 
ite | metainacrions|INSTALLATIONS| NSPAL Tons SEALE RZIONS 
Area per (Such as Offices, (Such as Stores, |hoodStores,Storage| Areas in Garages 
Outlet Drafting Rooms, School Rooms) | Areas in Factories*) and Unimportant 
Factories, etc.) and Basements) Basements) 
Square Wattage Capacity | Wattage Capacity | Wattage Capacity | Wattage Capacity 
Feet per Outlet per Outlet per Outlet per Outlet 
65-75 300 200 150 100 
75-85 300 250 150 100 
85-95 350 250 200 100 
95-110 400 300 200 100 
110-125 450 350 250 150 
125-140 500 400 250 150 
140-160 600 450 300 150 
160-190 700 500 350 200 
190-220 800 600 400 200 
220-260 950 700 450 250 
260-300 1100 800 550 300 
300-340 1250 950 650 300 
340-390 1450 1100 750 350 
390-440 1650 1250 850 400 
440—500 dts 1400 950 450 
500-560 ce Ne 1600 1050 500 
560-630 ae 1800 1200 590 
630-710 a oie Lee 1350 650 
710-800 Macs SWS 1500 750 
800-900 ae ee 1700 850 

















* In factories it is often desirable to convert storage areas into work places to meet immedi- 
ate production needs. For this reason, it is recommended that storage areas be wired 
according to Class B specifications. 


10 











LOCATION OF OUTLETS—ADEQUATE WIRING 








Voltage Drop—Wire sizes for all classes of lighting installations should be 
such that the voltage drop between the panel bor and outlets does not exceed 
2 volts, computed for each length of run and for an allowance in capacity per out- 
let as given in Table 3. Table 4 shows the wire size required for various conditions. 


TABLE 4—WIRE SIZE REQUIRED 


(Length of wire for a circuit is double the length of run) 


WATTS PER CIRCUIT 





eicieieglieiegiegiegieglieiece eiceielie/sieic Se 
30 aly ltal vs loalaalaa lag 14} 14) 14) 14] 14 10} 10} 10) 10} 10 


The difference in the cost of 
an : oie 
40 14 iting vite rot aedthead. 14| 14] 14] 14] 12| 12] 12] 10| 10| 10 | 10] 10 
vantages generally sufficient, 


50 14 that many electrical men 14] 14} 12] 12] 12] 12 


specify No. 12 asthe minimum 

































10] 107 8] 8 
60 14 size for branch circuits. 14712] 12) 12410] 10 Sime SeG ES 
70 14] 14] 14] 14] 14) 14] 14712) 12] 12] 12710] 10 8] 8 8 6 
& 80 114] 14) 14] 14] 14| 14) 12] 12 8| sl 6| 6 
= ae ee, 
= 90 14] 14] 14] 14] 14] 12] 12] 12 6| 6| 6| 6 
=) 
© 100 14] 14} 14] 14] 14,12] 12] 12 6 6] 6 
= 110 14| 14) 14] 14 10 6 6] 4 
As 120 14] 14) 14) 14 10 6 4) 4 
e 
ey 130 14] 14] 14] 14 10 6 4) 4 
| 
ZI 140 14} 14} 14) 14 10 6 4} 4 
& 150 14] 14 | 14 10 4 4) 4 
Z 160 14] 14] 14 8 4 4] 4 
fe 
170 14] 14] 14 8 oe 
ic) This table shows the wire size required 
° 180 14| i4| 14 8 for 115-volt circuits of various lengths of < 9 
= run, based on a drop of two volts be- a 
= tween the panel board and the outlets. 
cw 190 14 8] 8 It is difficult in branch circuits, at 2} 2 
A oe walt Se Aaa meets to use 
w arger than No. 8 wire because of the 
=) 200 14 8 iS diioukey of handling in conduit. Where 2) 2 
; the proper wire size‘for a din- . 
210 14 8} 8 stallation, ceria’ to dant table: - 2) 2 
larger than No. 8, it is usually best either 
220 14 8/ 8 to provide more circuits with less load, 2] 2 
or to pelocate pear Nata llas 
. crease lengths of run. e dott i 
230 14 8) 8 shows the usual wractical limits for a 2} 1 
cuit load and length of run. 
240 14 8] 8 ] 
250 14 8) 8 1 


Note—These recommendations on wiring are based on the allowances of The National Code: 
i. e. circuits equipped with medium screw sockets limited to 15 amperes and not more than 
12 outlets per circuit; mogul sockets—limited to 40 amperes and 8 outlets per circuit. Present 
wiring practice is usually well within the limit allowed by the code. In some cases it is necessary 
to meet other requirements of local codes. 


11 


2. Foot-Candles Required 


Foot-candle recommendations are 
7 based on research studies of vision, on 
= observations of results in actual installa- 
tions and, furthermore, on the adequacy 
of present equipment and methods to 
provide the desirable standard of illumi- 
nation with safety and economy. All 





2 l : ae 
Med his ane laboratory data point to the desirability 


of higher levels of illumination from the 
standpoint of vision, and practical tests 
substantiate the economy which results 
because of increased production, fewer 
accidents, and similar benefits. 


But without regard to such factors 
which are basic considerations of lighting 
poe ec economics, because of the progress the 

electric industry has made, tending to 
lower costs of energy and lamps, 30 foot- 
candles cost no more today than 3 
foot-candles cost twenty-five years ago. 





120 





100 Foot-Candles 100 
(Daylight near windows) 


LIGHT and TIME 
required for 


PERCEPTION 


oO 
io} 





D 
(oe) 








10 Foot-Candles 
(Artificial light—modern system) 


Foot-candles of illumination 
K 
oO 





20 











1 2 
1 Foot-Candle : . 
(Artificial light—old style system) Relative time 


The eye functions over wide range lighting conditions as illustrated by the 

photographs at the left; the graph at the right is the scientist’s quantitative 

statement of what everybody has experienced, namely, the eye sees more and 
sees more quickly as the illumination level is increased. 


12 


FOOT-CANDLES REQUIRED 


The foot-candle values given in the following pages correspond 
to present standards for different classes of industrial operations, 
offices, stores, etc. They are merely an index to good practice. 
In most cases, where higher foot-candle values than shown in this 
table are being used, it is found that the benefits derived more than 
offset the slightly increased cost. The desirable illumination for 
any particular installation depends upon actual conditions, such as 
the accuracy of the operation, the fineness of detail to be observed, 
the color of the goods worked on or handled, and, in the case of 
stores, the advertising value resulting from the attractiveness of a 
well-lighted interior. . 

TABLE No. 5 
Present Standards of Foot-Candles of Illumination for 
COMMERCIAL INTERIORS 


Foot-Candles Foot-Candles 


Recommended Recommended 
Good = Mini- Good Mini- 
Practice mum ; Practice mum 

Armories: Dance Hallsge--neiniesn es 6 4 
DrilliShedseenoucim cinerea 10 6 
Exhibition Halls......... 12 8 Dental Offices: 

: Wialtin ci OOnl ene at 6 4 

Art Galleries: Operating Office......... 12 8 
ede etare Sten ae oe ta ad ae ~ 3 Dental Chairssnee ee 50 25 

tings eee — 
as ay er Depot—Waiting Room..... 8 5 

AUICILOTININS ore eee 5 . 

; Drafting, Roomy... 22 4 00n 25 15 

Automobile Show Rooms... 15 10 

Bank: Elevators: 

eee 10 6 Freight and Passenger... . 6 4 
Cages and Offices.:...... 15 10 Fire Engine House: 

Barbershop aeeeeieeeren: 15 10 eee Aor is turned in. . 8 By 

Base Ball—Indoor Game... 15 10 BY O thes Bins ete a Y a 

Basket Boll seees ae eae ee 15 10 co timer ier aces - ; 

: rage—Dead.......... 

Bowling: Lives eae ; 8 5 
OnAlley, RunwayandSeats 8 5 Repair Dept. and Washing 15 10 
Oni Pins: 3s sore eee 25 15 2 

Billigede. Goal 6 A Gymnasiums: 

Leer Nie ante eae RE ODS Main Exercising Floor.... 12 8 
On Table........ a a Swimming Pool.......... 8 5 
Cars: Side oe Lae niaenee 6 4 
ps Ce cker FROOMS i. co ene 6 4 
paee ae posh odes 8 el Fencing, Boxing, Wrestling 12 8 
Mail: , 
en ee 12 g_——“Hialls, Passageways in Ine 
aia Cases iar caess 8 a BS aay 
torage............ yee Handball oercermsre ces oe ele 25 1 
Street Railway and Subway 10 6 oe? 
Hospitals: 
Churches: * 
Andi tori see ities 3 2 Robby end Beopucn Room ° . 
Sunday aeuoe) Room..... ‘ 5 OLFFIGOLIS. cee esc ccc cc ces 
Pulpit or Rostrum....... 2 8 : : oo 
Art Glass Windows... ... 25-50 15 bile het ie ban wun = 47 ; 

Club R : Private Rooms.......... 8 D 

lee : : Night Mumination.....-. onto oe 

Be a a oe ate a a perating Ol Mesatetternre 00-200 7 
Reading Room.......... We = Operating Room......... 15 10 
Court Rooms sysc- resets 10 6 Laboratoriesneny eee ee 15 10 


FOOT-CANDLES REQUIRED 


TABLE No. 5 (Continued) 


Present Standards of Foot-Candles of Illumination for 


COMMERCIAL INTERIORS (Continued) 


Foot-Candles Foot-Candles 
Recommended Recommended 
Good Mini- Good Mini- 
Practice mum Practice mum 
Hotels: Two to four 
Lobby ene eee 8 5 Show) Cases tactic times that of 
Dining Roomeree eee 6 4 store proper 
Kitchens eee cero ee 10 6 Show Windows: 
Bed Rooms............. 8 5 Large Cities— 
Gorridors can ancaaees c 3 2 Brightly Lighted District. 150 100 
Writing Room........... 12 8 Secondary Business Loca- 
. F UONo cs souadcoaanoucodar 165) 50 
cash to haces 13 , Neighborhood Stores. .... 50 30 
elegance pee xe) edium Cities— 
Stacks Roome seer eee 6 4 Brightly Lighted District. 15 50 
De ek, ACI 6 4 eighborhood Stores... .. 50 30 
EEE SOUS Small Cities and Towns... 50 30 
hunch # Roommate 12 8 Lighting to Reduce Day- 
Market 2 8 light Window Reflections. 200-1000 
ae gh Ser es Stores—Department and 
Moving Picture Theatre: Lara eore ee: ae 
During Intermission...... 5 3 Manu BlOOrsssceieeeaiene 15 10 
During Pictures......... 0.1 Others loorsse eee 12 8 
Musou: Basement Store.......... 15 10 
General S33 cee ee 8 5 Stores—Medium Size: 

Special Exhibits......... 25-100 10 Art marci acne eee net 12 8 
Office Buildings: puremelae Supplye erie 1 
; eShopsceeeenrreor onc 

Private and General Offices— Books eee 12 8 
@loses Works ea eenere 15 10 Chita oe eee a. 12 8 
No Close Work.......... 10 8 Cigars eee ae 15 10 
Eile oom Fete ees : A nee lls SOREN ae RSS ie 10 
OE OnreCHIONEry enone 2 8 
Reception Room......... 6 4 Dairy Products.......... 12 8 
Post Office: Perortoe x cieats sea nia ertene ie # 
Lobby. ja = 22022 s0 loam. Dry Goods..00000000)11) 1B 
Soran Matt ise ts ge a Sletten uspty at Bit 
Private and General Offices 15 10 Ponte, Pe ae a ee ie ‘ 
File Room and Vault..... 6 4 Grocery Scns tie ne 12 8 
Corridors and Stairways. . 3 2 Haberdashery........... 15 10 
Railway: Hardware jit s- eco 12 8 
Depot—Waiting Room... 8 5 vat aoa, Gh elena cotenemer oyna 15 10 
(ticket. Ofiices wee eee 12 8 pe PES ae q 15 10 
Rest Room, Smoking Room 8 5 Teonka’ OS eo 12 
Baggage Checking Office. . 12 8 Me: DPD SORE Gib Baba C 12 8 
Storage cae eee 6 4 Main FORD tO AO AOS 15 ib 
Goncourse® 2756 one 6 4 Masa CSO 5 22RD 12 : 
5 ee VLUSIOS eet ite ace 
Train Platform.......--. 9 ia INGtiOnS Senet ieee eee 12 8 
Restaurants 3.0 scone cure 8 5 viene Bastin Pe Oe 12 8 
OG Hitcoec at ore scote phocontee 15 10 
Racquet 2:2 eo okinennle 25 15 Sporting Goods.......... 12 8 
Schools: ‘Tailor =p er eere ee 15 10 
INGOT ENN, on omcounbE 8 5 lObaCCOMma rete ite 15 10 
Class Rooms, Library and Variety Store nee eee 15 10 
CON een ices eee yettete 12 8 Telephone Exchanges: 
eee: and Stairways. . ee i poarlna learns a Yeas ove att 8 5 
Laboratories...........- 12 8 Gi hlec\antcetaes ae =e 6 | 
Manual Training........ 12 8 a Ee meee 
Sewing Rooms... 25 15 ennis (indoor) erate ene 25-50 15 
Study Room—Desks and Theatres: 
Blackboards. . 12 8 AUdItOriUIn acer 3 2 
Skating Rink eee Ue 8 5 kes ee a ic P 
Squash oi. sey iacte eres 25 15 Toilet and Washrooms.... . 6 4 


14 


FOOT-CANDLES REQUIRED 


TABLE No. 5 (Continued) 


Present Standards of Foot-Candles of Illumination for 


INDUSTRIAL INTERIORS 


Aisles, Stairways, Passage- 


Automobile Manufacturing: 


Automatic Screw Machines 
Assembly Line.......... 
Frame Assembly......... 
‘LooliMaking= ee cme 
Body Manufacturing— 

Assembly, Finishing and 
Inspecting’. -cictoeren eine 


Bakeries Sercctesssieicicle on revere 


Book Binding: 


Folding, Assembling, Past- 
Ing ).etCte oon oak aoe 
Cutting, Punching and 
Stitching 7. eee re 
Himbossing ys .102 2 cienals ei 


Gandy, Making yeeieris)essrels 


Canning and Preserving... . 


Chemical Works: 


Hand Furnaces, Boiling 
Tanks, Stationary Driers, 
Stationary or Gravity Crys- 
tallizinge een es eee 
Mechanical Furnaces, Gen- 
erators and Stills, Mechan- 
ical Driers, Evaporators, 
Filtration, Mechanical 
Crystallizing, Bleaching. . 
Tanks for Cooking, Ex- 
tractors, Percolators, Ni- 
trators, Electrolytic Cells. 


Clay Products and Cements: 


Grinding, Filter Presses, 
Kiln. Rooms san aero 
Molding, Pressing, Clean- 
ing and Trimming....... 
Enameling?..2. eee eric 
Color and Glazing. ...... 


Cloth Products: 


Cutting, Inspecting, Sew- 
ing— 

Paght Goods. terrier 
DarkiGoods\ecn ae. use aes 
Pressing, Cloth Treating 
(Oil Cloth, etc.)— 

Light Goods............ 
Darke Goods ).ceet ee 


Coal Breaking and Washing, 
Screening: 390s. hiaae ses 


Foot-Candles 
Recommended 
Good Mini- 
Practice mum 
3 2 
8 5 
12 8 
20 12 
50-100 25 
15 10 
15 10 
12 8 
20 12 
50-100 25 
12 8 
8 5 
12 8 
15 10 
12 8 
12 8 
5 3 
6 4 
10 6 
5 3 
8 5 
10 6 
15 10 
15 10 
50-100 25 
12 8 
20 12 
5 3 


15 


Construction— 
Indoor General.......... 


Dairy Products s--e-e eee 


Electric Manufacturing: 
Storage Battery, Molding 
of Grids, Charging Room. . 
Coil and Armature Wind- 
ing, Mica Working, Insu- 
lating Processes.......... 


Elevator—Freight and Pas- 


Engraving. ieee ere 
Forge Shops and Welding... 


Foundries: 
Charging Floor, Tumbling, 
Cleaning, Pouring and 
Shalang.Outpeeeeeeee 
Rough Molding and Core 
Making: etscse cme ae ee 
Fine Molding and Core 
Making vec a... eee ae 


Garage—Automobiles: 
borseces Dead Slaetecice 
Repair Deptacd Washing 


Glass Works: 

Mix and Furnace Rooms, 
Pressing and Lehr, Glass 
Blowing Machines. ...... 
Grinding, Cutting Glass to 
Sizejoilveringeeeeeen ee 
Fine Grinding, Polishing, 
Beveling, Inspection, Etch- 
ing and Decorating...... 
Glass Cutting nie less) 
Inspecting Fine.. 


Glove ee poe 
Light Goods— 
Cutting, Pressing, Knitting 
Sorting, Stitching, Trim- 
ming and Inspecting..... 
Dark Goods— 
Cutting, Pressing, Knitting 
Sorting, Stitching, Trim- 
ming and Inspecting..... 


Hat Manufacturing: , 
Dyeing, Stiffening, Braid- 
ing, Cleaning and Refin- 


Forming, Sizing, Pouncing, 
Flanging, Finishing, L[ron- 


Foot-Candles 
Recommended 
Good Mini- 
Practice mum 
5 3 
12 8 
10 6 
20 12 
8 5 
50-100 25 
10 6 
8 5 
10 6 
15 10 
3 2 
8 5 
15 lu 
10 6 
12 8 
15 10 
25-50 15 
12 8 
15 10 
15 10 
50-100 25 
10 6 
15 10 
12 8 
15 10 
15 10 
50-100 25 


TABLE No. 


5 (Continued) 


Present Standards of Foot-Candles of Illumination for 


INDUSTRIAL INTERIORS (Continued) 


Foot-Candles 
Recommended 
Good Mini- 
Practice mum 
Ice Making: 
Engine and Compressor 
Roont nee seein ae ace 10 6 
Inspecting: 
Rough .caccceo es cect 10 6 
Mediuiaiiinic « otisuewesiere oe ss 15 10 
Fine «06 os Su omaaton 25 15 
Extra Wines. acc .cet ce oe 50-100 25 
Usually requires 
glint reflections 
Polished Surfaces........ from specially 
located light 
source 
Jewelry and Watch Manu- 
facturing). dase ene oe 50-100 25 
Laundries and Dry Cleaning 12 8 
Leather Manufacturing: 
WatsAcarciecte cmearhee tenets: 5 3 
Cleaning, Tanning and 
Stretching ase eeoeee eee 6 4 
Cutting, Fleshing and Stuff- 
ING sek eee 10 6 
Finishing and Scarfing... . 15 10 
Leather Working: 
Pressing, Winding and 
Glazing— 
La ght 5.) ascaccthon atatshe ote 12 8 
Darkane cc aero 15 10 
Grading, Matching, Cut- 
ting, Scarfing, Sewing— 
Lightnin ee ae 15 10 
Dark ayicins 6 sontinen ae 50-100 25 
Locker Rooms............. 6 4 


Machine Shops: 


Rough Bench and Machine 
Work?) Syn Se ae 10 6 
Medium Bench and Ma- 
chine Work, Ordinary Auto 
matic Machines, Rough 
Grinding, Medium Buffing 
and Polishing. ......... 15 10 
Fine Bench and Machine 
Work, Fine Automatic Ma- 
chines, Medium Grinding, 
Fine Buffing and Polishing 20 12 
Extra Fine Bench and Ma- 
chine Work, Grinding (Fine 
Wiorktecae. ccm ee. 50-100 25 


Meat Packing: 


Slaughtering............ 8 5 
Cleaning, Cutting, Cook- 
ing, Grinding, Canning, 
Packing ici Sere ote 12 8 


Milling—Grain Foods: 


Cleaning, Grinding and 
Rolling Sis -creen eee 
Baking or Roasting...... 
Flour Grading........... 


Offices: 


Private and General— 
Close Work............. 


Packing: 


Crating 3.47 eee eee 
Boxing jenn eee ee 


Paint Manufacturing....... 


Paint Shops: 
Dipping, Spraying, Firing. 
Rubbing, Ordinary Hand 
Painting and Finishing. . . 
Fine Hand Painting and 
Minishin see eee 
Extra Fine Hand Painting 
and Finishing (Automobile 
Bodies, Piano Cases, etc.) . 


Paper Box Manufacturing: 


Paper Manufacturing: 


Beaters, Machine, Grinding 
@alendering=)eee eee 
Finishing, Cutting and 
(rimming seer eee 


Polishing and Burnishing.. . 


Power Plants, Engine Rooms, 
Boilers: 


Boilers, Coal and Ash 
Handling, Storage Battery 
Roomszereea noe cee 
Auxiliary Equipment, Oil 
Switches and Transformers 
Switchboard, Engines, Gen- 
erators, Blowers, Compres- 
SOPS sees cece eee ee 


Printing Industries: 


Matrixing and Casting, 
Miscellaneous Machines, 
Presses #96. pe ee 
Proof Reading, Lithograph- 
ing, Electrotyping....... 
Linotype, Monotype,T ype- 
setting, Imposing Stone, 
Engraving so eee 


Receiving and Shipping 
16 


Foot-Candles 
Recommended 


Good Mini- 
Practice mum 


8 5 
12 8 
25 15 
15 10 
10 8 
25 15 

6 4 
10 6 
10 

8 5 
12 8 
15 10 

50-100 25 
10 6 
12 8 

5 3 

6 4 
10 6 
12 8 

8 5 
12 8 

5 3 

8 5 
10 6 
12 8 
15 10 

50-100 25 

6 4 











FOOT-CANDLES REQUIRED 








TABLE No. 5 (Continued) 


Present Standards of Foot-Candles of Illumination for 


INDUSTRIAL INTERIORS (Continued) 


Rubber Manufacturing and 
Products: 


Calendars, Compounding 
Mills, Fabric Preparation, 
Stock Cutting, Tubing Ma- 
chines, Solid Tire Opera- 
tions, Mechanical Goods 
Building, Vulcanizing.... 
Bead Building, Pneumatic 
Tire Building and Finish- 
ing, Inner Tube Operation, 
Mechanical Goods Trim- 
ming; CLreading>..-04- 


Sheet Metal Works: 


Miscellaneous Machines, 
Ordinary Bench Work.... 
Punches, Presses, Shears, 
Stamps, Welders, Spinning, 
Fine Bench Wor 


Shoe Manufacturing: 


Hand Turning, Miscella- 
neous Bench and Machine 


Inspecting and Sorting Raw 
Material, Cutting, Lasting 
and Welting (Light)...... 
Inspecting and Sorting Raw 
Material, Cutting, Stitch- 
img) (Dark) eee eer ee 


Soap Manufacturing: 


Kettle Houses, Cutting, 
Soap Chip and Powder... 
Stamping, Wrapping and 
Packing, Filling and Pack- 
ing Soap Powder.. : 


Steel and Iron Mills, Bar, 
Sheet and Wire Products: 


Soaking Pits and Reheating 
Wurnacessnnace seria 


Floo: 

Muck’ and Heavy Rolling, 
Shearing, rough by gauge, 
Pickling and Cleaning... . 
Plate Inspection, Chipping 
Automatic Machines, Red, 
Light and Cold Rolling, 
Wire Dravine phowine, 
fine by line.. ee 


StoneCrushingandScreening: 


Belt Conveyor Tubes. 
Main Line Shafting, 
Spaces, Chute Rooms, In- 
side of Bins:5.. 3. foes 
Primary Breaker Room, 
Auxiliary Breakers under 
ime RI OS ee OCR ODI 


Foot-Candles 
Recommended 
Good Mini- 
Practice mum 
12 8 
15 10 
12 8 
15 10 
25 15 
12 8 
15 10 
50-100 25 
8 5 
10 6 
3 2 
6 4 
8 5 
25 15 
12 8 
3 2 
5 3 
8 5 


Ly 


Foot-Candles 


Recommended 
Good Mini- 
Practice mum 
Store and Stock Rooms: 
Rough bulky material... . 3 2 
Medium or fine material 
requiring car6...)) 0. 8 5 
Structural Steel Fabrica- 
tion te Ae este ae 10 6 
Sugar Grading* see 25 15 
Testing: 
Roughss.cush cee 8 5 
Fine aie Mae nee 15 10 
Extra Fine Instruments, 
Scales etedie ras 50-100 25 
Textile Mills: 
(Cotton) — 
Opening and Lapping, 
Carding, Drawing-frame, 
Roving, Dyeing.. 8 5 
Spooling, Spinning, Draw- 
ing-in, Warping, Weaving, 
Quilling, Inspecting, Knit- 
ting, Slashing (over beam 
00d) eee eae: eae 12 8 
(Silk )— 
ee Throwing, Dye- 
er Meche of ashe baaee ip, 8 
Quilting’ Warping, Weav- 
ing and Finishing— 
LightiGoods Seeman 15 10 
Dark Goods............. 20 15 
(Woolen)— 
Carding, Picking, Washing 
and Combing ian 6 4 
Twisting and Dyeing..... 10 6 
Drawing-in, Warping— 
Light.Goods mena entans 10 6 
DarkGoods incu aoe 15 10 
Weaving— 
LightiGoods See eeee ee 12 8 
DarkiGoodss.ncsneneee: 20 12 
Knitting Machines...... . 15 10 
Tobacco Products: 
Drying, Stripping, General 3 2 
Grading and Sorting..... 25 15 
Toilet and Wash Rooms.... 6 4 
Upholstering: 
Automobile, Coach and 
Hurnittire ss arene 15 10 
Warehouse seria citer ec: 3 be 
Woodworking: 
Rough Sawing and Bench 
‘Worker eee ee 8 5: 
Sizing, Planing, Rough 
Sanding, Medium Machine 
and Bench Work, Gluing, 
Veneering, Cooperage wotaen 12 8 
Fine Bench and Machine 
Working, Fine Sanding and 
Minish since eee 15 10 


FOOT-CANDLES REQUIRED 


TABLE No. 5 (Continued) 


Foot-Candles Illumination for 


OUTDOOR LIGHTING 


These values are included for reference purposes although the special 
considerations of design are not covered in this bulletin. 


Foot-Candles Foot-Candles 
Recommended Recommended 
Good Mini- Good Mini- 
Practice mum Practice mum 
G : ae at 
Automobile Parking Spaces. 1 0.5 epee oe, fer 15 10 
Baseball Diamond (Indoor Yard and Driveways..... 4 2 
Game).......--..-+..+5-- 10 9 Horseshoe Pitching........ 6 4 
Basket; Ball jcc). enone ree 6 4 loe Hockey 8 5 
Bathing Beaches........... 1 0.5 Loading Docks............ 3 2 
Bulletin and Poster Boards: umbersY ards. eee 1 0.5 
Bright Surroundings— Sha ttag rn 
Light Surface........... 30 20 SUNITA ts boo como dimooae 3 2 
DarkiSurtacc eae 50 30 Track eee 15 10 
Dark Surroundings— Monuments (See Building 
Light Surface........... 15 10 Exteriors) 
Darky ouriacesceeeia 30 20 oats 
. reight (See Loading 
Bicese De A ACH ees Nell eae 3 2 Docks) 
Ring eee een 80 50 Passenger... sine ae verte 4 2 
Building: Play grounds2.. nee 4 73 
Construction Work...... 6 4 Polo eee nese a= ees 8 i 
Excavation. ............ . : Prison: Vardar 3 2 
omits Heoie apa Mon- Protective Industrial....... 1 0.5 
Bright Surroundings— Quarries - 0.2 2 Sener se 3 2 
Paghtiouriace errr 10 6 Railway Yards: 
Dark purtacess. eer 20 15 General eh @cecer ecee 0.25 0.15 
Dark Surroundings— Scale: Housesa.s eee ee 3 2 
ight) Surtace anise 6 4 Roque ase sci teeta eionpet 6 4 
DarkjSuarfaces. sae 12 8 Signs—Painted (See Poster 
Church Windows (Art Glass) 25-50 5S Boards) 
ee ‘ Ship Yard Construction.... 6 4 
EVES esate tert ot ricoh val clke yey = nos 2 - 
Kconeat ee ee 10 6 Skating .c-ceont cee ae 2 1 
Storage.Y ards. eee 1 0.5 
Glock’ Golfse cn aceeee kee 10 6 é A 
Croquet Staetiws-irdes atte 6 4 Swimming 2001s eae a : 
‘ iLarget shooting see 20 15 
Dredging as oes ne see 2 1 
eas ‘Vennis!| Courts. eee 25-50 15 
Drill Pields*otee eee 3 2 Tob Slid 2 1 
Flags—Floodlighted........ 25-50 15 eas Seger 0 Fg 
Football (lrattic Officers race te 20 10 
Practica ean ne 6 4 Trap Shooting........ Bete 15 10 
Gramesigyies setepre sacha 12 8 Volley: Ball 82.0. 15 10 


STREETS AND THOROUGHFARES 


Lamp Lumens per 
Linear Foot of 


ates Street 
Business District: 
White Way—Large, City car a0%0 Aare oe ee ee CTE RE ree ares eee 500-2000 
Small Citys. shane <-.c e  e  er aee 200-500 
Park: Boulevards sie 2 Sees oie: Sal Se ae et re Boe ao, Se Ce See 50-100 
Thoroughfares and Wholesale Districts .......................00000 eeu 50-200 
Residence Streetal. orcictees o ctelecsecavers. 5 peer vera Mek yer SoMa nite ee ba ene tree ae 20—40 
Outlying: Districtsiand/Alleys snes. 5 he eee ee ee : 5-10 
Phi ghiweaye ftebe vars ojscoveneie oeyeisee hehetire: 8 o.oo a SR Me ee Ae rent en a 10-20 


stil) 


Reflection Factors 


The proportion of light reflected by walls and ceilings of various colors, that 
is, their Reflection Factors, has an important bearing on both the natural and 
the artificial lighting. The proportion reflected will depend somewhat upon the 
color of the incident light. The figures here given show what proportion of 


No. 1 
White 
Papert 
80% 





No. 2 
C* Gat 
aft ; 67% 


€-) N OF 83 
urrg Gray 
’ 60% 





Gray 


i i i nee ; hy. . oe ss ics re Ne No. 4 
& 2 ey a S oe! : ps a o 
ee) 549, 





No. 5 
Gray 


39% 


No. 6 


French 
Gray 


38% 


No. 7 
Gray 
28% 


No. 8 
Gray 


17% 














No. 9 
Ivory 
White 


78% 


No. 10 
Caen 
Stone 


73% 


No. 11 
Ivory 


71% 


No. 12 
Ivory 
Tan 


64% 


No. 13 
Primrose 


70% 


No. 14 
Lichen 
Gray 


69% 


No. 15 
Pearl 
Gray 


74% 


No. 16 
Silver Gray 
and Caen 
Stone 


57% 


of Colored Surfaces 


the light of Mazpa lamps these painted surfaces reflect. Reflection Factors are of 
special usefulness in determining the Coefficient of Utilization (ratio of light de- 
livered at the work to total light of lamps) applicable to an interior. The Re- 
flection Factor of any colored surface can be approximated by comparing it with 
these samples. 











No. 17 | No. 25 
Buff Stone | marcar 
aac oe Green 
ure 
36% 18% 
No. 26 
Ae Je Olive 
Green 
54% ae 
No. 19 No. 27 | ‘ 
Buff Stone Ley ue iy 
42% $30, | 
No. 28 ve 
Pale Azure a) iva 
38% iy 
No. 29 
Sky Blue 
35% 
Sa oe No. 30 ' 
we Shell Pink P. 
Green 5 ) in) 
61% | re 49% 
No. 23 
Bright Sage No. 31 
and Ivory Pink 
an 49% 
53% 
No. 32 
Cardinal 
e 
18% 





$1712 E27 794 


Buik 


3. Room Efficiency and Reflector Characteristics 


In order to specify the lamp size necessary to provide the 
foot-candles desired, the first step is to determine the percentage of 
light emitted by the lamp that actually gets down and is useful 
on the working plane. This percentage is called the Coefficient of 
Utilization for the particular installation. 


A simple “watts per square foot’’ specification is unreliable 
unless applied with the benefit of experienced judgment of various 
factors which affect the result. Interior finish, size and proportions 
of the room, the type of reflector, and maintenance conditions 
are variables which must be taken into account. Unless due 
allowance is made for each of these the results vary, in many 
cases 5 to 1; in other words, the same wattage per square foot 
might produce 15 foot-candles under certain conditions and only 
3 foot-candles under a combination of unfavorable conditions. 
Coefficient of Utilization Tables, Pages 24 to 29, give the net 
efficiency result with due regard for the important variables 
noted below. 


Interior Finish—The paint samples show the percentage of 
light from Mazpa Lamps reflected by various colors; the holes in 
each sample permit convenient comparison with actual interior 
finishes. It will be noted that the influence of the interior finish is 
least important with opaque direct lighting reflectors, more pro- 
nounced with translucent glass units and a major consideration with 
semi-indirect and totally indirect luminaires. 


Room Proportions (Room Index)—In general, large rooms 
use light more efficiently than do small rooms because there is 
less wall area to absorb light in proportion to floor space. Raising 
the light source tends to increase the proportion of wall area to 
floor area, thus reducing the relative efficiency of high bay installa- 
tions. It will be observed that a room 10 feet square with a 
10-foot ceiling has a Room Index of 1. Room Index values are 
computed with a unit room of this character as the basis. 


The effect of room proportions on illumination efficiency, and 
its importance in actual design problems will be noted by comparing 
the Coefficient of Utilization for example, for a room having a 
Room Index of 0.6 against one of 5.0, other factors remaining 
constant. 

19 


ROOM EFFICIENCY AND REFLECTOR CHARACTERISTICS 











Reflector Characteristics*—The selection of a suitable type 
of lighting unit depends not only upon its efficiency, the proper 
distribution of light and the requirements of the work, but, in the 
case of indirect units, upon the construction of the room and color 
of ceiling and walls. Decorative appearance frequently is an impor- 
tant item. 

A lighting installation may be judged by seven fundamentals 
described on page 21, and in Table 7 various lighting units are 
rated in accordance with these criteria. 


AT pBxcetten B. Good Gu rain 
_ B- ; < 
B 1 perv Good C 7 per Fair D_ Unsatisfactory 


The relative importance of these ratings should be carefully 
weighed with respect to the particular application at hand. For 
instance, in an office the criteria of major importance would rank: 
(1) Direct Glare, (2) Reflected Glare, (3) Shadows; (4) Illumination 
on Horizontal. On the other hand, ina foundry with lamps mounted 
high the order of importance would be: (1) Illumination on 
Horizontal, (2) Vertical Illumination, (3) Maintenance. A rating of 
D under Reflected Glare would not disqualify a unit except for use 
above polished metal or other highly glazed surfaces. 


Procedure 


To Determine the Coefficient of Utilization for the Installation 


Refer to Table 6—Room Index, which classifies the room according to its 
proportions. From this table find the Room Index which corresponds most 
nearly to the dimensions of the installation. Apply this in the use of Table 7. 


Refer to Table 7—Coefficients of Utilization, which gives the proportion 
of the generated light from the lamps which reaches the plane of work. 
The Coefficient of Utilization for the installation of the type of lighting unit 
selected will be found in the proper column of wall and ceiling color, opposite 
the correct Room Index. 


*Note: It is important that good reflecting equipment be installed. The 
luminaires shown in Table 7 illustrate common types under which most reflectors 
on the market can be classified for purposes of design calculations. For example, 
No. 8 is a unit of a general type of which there are a great variety made by 
various manufacturers. Of two or more units of the same type the choice should 
be governed by considerations of brightness, diffusion, absorption, appearance 
and cost, but not by cost alone. Of two samples of glass enclosing globes, out- 
wardly identical, one may absorb 30% of the light and the other only 15% for 
the same degree of diffusion. The safest plan is to choose products of reliable 
manufacturers. 


20 


‘ROOM EFFICIENCY AND REFLECTOR CHARACTERIS 



































ICS 


Illumination on Horizontal Surfaces is a prime 
requisite in offices, drafting rooms and those shops where 
the problem is to provide the best illumination for sustained 
vision of flat surfaces on the horizontal or slightly oblique 
planes in which papers, books and other flat objects are 
usually examined. For relative performance of various 
units compare coefficients of utilization for any given 
condition. 


Illumination on Vertical Surfaces is essential in 
many industrial operations where working surfaces are 
in vertical or oblique planes. It is likewise important in 
stores with vertical shelving, rug racks, etc., in art museums, 
library stock rooms, office file rooms. Without supple- 
mentary units, the illumination on vertical surfaces from 
ordinary general lighting units is of the order of one-half 
to one-third of the horizontal illumination values. 


Appearance of Lighted Room refers only to the 
general or casual effect produced by the complete system, 
and is not intended to rate the unit as to satisfaction from 
the standpoint of good vision or freedom from eye fatigue. 


Direct Glare is the most frequent and serious cause 
of bad lighting. It results among other things from 
unshaded or inadequately shaded light sources located 
within the field of vision, or from too great contrast 
between the bright light source and a dark background or 
adjacent surfaces. Glare should be avoided by the use 
of proper reflecting and diffusing equipment. 


Reflected Glare from polished working surfaces is 
particularly annoying because of the necessity of directing 
the eyes toward those surfaces, and further because the 
eyes are by nature especially sensitive to light rays from 
below. The harmful effects of this specular reflection can 
be minimized by properly shielding from below or diffusing 
the source. 


Shadows, that is, differences in brightness of surfaces, 
are essential in observing objects in their three dimensions, 
but are of little or no value in the observation of flat 
surfaces. Where shadows are desirable, they should be 
soft and luminous, not so sharp and dense as to confuse 
the object with its shadow. 


Maintenance Requirements depend upon contour of 
reflector, construction of fixture, and average maintenance 
conditions. The rating is based upon the likelihood of 
breakage, the labor involved in maintaining the units at 
comparable degrees of efficiency, and indication given 
of need of cleaning. 


21 























FEET 











TABLE 6 
ROOM INDEX FOR NARROW AND AVERAGE ROOMS 











ROOM EFFICIENCY AND REFLECTOR CHARACTERISTICS 























° ° 
Hs Hs ee 6 PELLICLE D/OooMAclomaooolmrnoonnlooammunloammun 
19 6° si oo SSSSSRISSOCRHRRISC CH ARR RP SHR RSI RHR RRS a 
g 
2 & 
° ° ream 
om es Orwre] Cowon CLRAAANALSOANNIRIONAMINM|ARROSS mncess o 
aN Se) ooo SSR SAI OCR SARIS RRR RRNA ARAN © © 
nN at i - 
ee 
i] 
0] ° 
° ° 5 & 
Ss es C0000 6 0 cS BLSA aa Sooqawnwirannce|mncece|moonmnmn! 2 B 
reN aye A oooo CRS SSSI R eee SAA NAIRS RNAI ANNAN Nd © 
=~ Las | I 
= ¢ 4 
Z s 
Sss 5 Sos mt JOWWRMMO/oLwnooS SAAWMMOINKROSSSSOIMMNSSSOloHMNNNH Sacsess| & 
so ea] on ooococors SSSA NIRS NNN NR RNAS ANNANAAINAM MOON 
coh! |e! tatanll PPS 
a |! fa) 
= © 
ARS ew a CALSSAIRLASOANW AMMESS[MSSOHUH/CoMnMMNN|MHSESSS weosessicscsessc 
as ao Scocdnie AAAANANAAANAAINANA A Alaa sola en en oslo i ai 
al a 
Ss Bee RASAANWISSANIMN IMIBOOCSwMISowmmmMunNjouunos|[rososo essssesisssss 
on BS COs s=s=—— ARANNANINNANANANINAN AMD NOD OD OD OD OD | OD OD OD SA SH SH SH HID 
ae c-) 
Eos ee SSAAWSIAANIIIROS SarwwwMopowwWoocoimosoosl[socoscco Ssessssissssse 
ao an addenda AAAAAMIAANMMS|NMM NN Olsaotdaal(saainwmwinhswmwwis 
a é 
pe! 
—“ ——. ra 
” ~ ° ° ° 2° rR) ° 
oS 80 = ED leowcen & Nes Noneot Honsos Wnco SS Mn cs SS Heo SSA 
Onsen Seer Oo IIIT RIES s ISS TT FSS AS aSSA8 5 
2 ol aioe gE |jeotoon SSSSISSISSSGSsessiesxesssienesssinssd 
iD m.o| | saans OHOSAADAOABIAGHSAG/ MH SRSS RAESATS|HSAS 
—— 
mr To 8 
= | 
oe TE 
S) »* | o 
O om of ~ = ~ — ie i 
| o aA ‘8 aN a a — = x ° 
x0 ue ES a S ” a q 
=O) g ar — ot San a N a oO? 
q0 AS | cs S a0 ay Na ot oo be 
cl ho = aw 6 a ro] nN C) 6 
o } ice) a an) aa) ~- ~~ ote 
60 68/8 * . y a g 
ts 
a x 


ROOM EFFICIENCY AND REFLECTOR CHARACTERISTICS 


TABLE 6 























ROOM INDEX FOR LARGE HIGH ROOMS 








37 to 
50 


























° 
bal =) 
nor) 
br) 

° ° 
a) ©o 
rio earl 
br) N 
° ° 
Po sm 
mi O19 me N 
= & 

3) —| 3/— 

| 9 mH! o 

bad —) C=) 
19 rN 
Nn I 

oe os 
a“ | | 38 
Se S-s 
oa as 
S38 Ss 
x= 1) 
———GN —_— 
we 2 
ga ge 
rep Sheed 

- 

ae) Ia) bo 
C.-C 
ce ae 
og »'S 
Oc o S| 
4s| = oy 
33 om © 
4 aS 
m Oo im © 
ov OD 
a=) a 


aooslaoan 
Cee s|COnRK 








Sopa 
Le ee oe ee Ae ee ee Bel 





naw c|agce 
SS SNS RNIN 








EEN Sg SS ee 
SAANIN AAA 











onnnlemce 
ACINANINA SM 


ROOM INDEX 





noos|oose 
NI OD Of) OD | OD OD SH OH 








SSSS|SSSS 
C9 oF oD 3 | i i 











ooosl|ooes 
bo nl feed tel te) 


(Feet) 


(Feet) 





Room Width |Room Length 





TABLE No. 7 
A GUIDE TO THE SELECTION OF REFLECTING EQUIPMENT 







RELATIVE FOOT- 
CANDLES FORAGIVEN| appear. 


LAMP SIZE ANCE OF | piRECcT | _, RE: MAIN- 
LIGHTING UNIT LIGHTED | GLARE | FLECTED | SHADOWS) teWaNce 


ROOM 








On 
Horizontal | Vertical 


Direct Lighting—General Industrial Reflectors 





RLM A B Be iB) BeBe eA 

White Bowl Lamp Excellent} Good Good Very Good Very Very 

90° to 180°—0% Good Good Good 
0° to 90°—66% 




















Glassteel Diffuser B + A B 
i ey Very |Excellent] Good 


90° to 180°—7% Good 


0° to 90°—60% 





ee | A+ 


Excellent 





3 


RLM Dome 
Dust-tight Cover 
90° to 180°—0% 
0° to 90 °—54% 













Satis- 
RLM Dome factory Excellent 
Clear Lamp above 






20-foot 
mount- 
ing 


Height 






90° to 180°—0% 
0° to 90 °—76% 




















D 


Concentrated 
Prismatic Reflector 
Aluminum Cover 

Clear Lamp 
90° to 180°—5% 
0° to 90 °—72% 


6 


Mirrored 
Glass Reflector 
Clear Lamp 
90° to 180°—3% 
0° to 90°—73% 





tse |) 4 


Excellent} Good 






Excellent 

















C A 


Fair | Excellent 








Excellent! Good Good 





ee 
Oxidized 
Aluminum Excellent} Good Good Very | Unsatis-| Fair Very 
Reflector Fair factory Good 
Clear Lamp above 
Polished 
90° to 180°—0% 
0° to 90°72 of Surfaces 
24 





TABLE No. 7 
AND COEFFICIENTS OF UTILIZATION 








PROBABLE AVERAGE ILLUMI- | CEILING 


NATION—AS FRACTION 


VERY LIGHT (70%) 





FAIRLY LIGHT (50%) | FAIRLY DARK (30%) 








































































FAIRLY | FAIRLY VERY FAIRLY | FAIRLY | VERY FAIRLY VERY 
OF INITIAL ILLUMINATION | Watts] LIGHT | DARK | DARK | LIGHT | DARK | DARK | DARK | DARK 
(50%) | (30%) | (10%) | (50%) | (30%) | (10%) | (30%) | (10%) 

Clean Average Dirty ROOM 
Conditions | Conditions | Conditions | 1/5 py COEFFICIENTS OF UTILIZATION 

Calculation Data—General Units 

0.6 32 28 25 sos 28 25 27 25 

8 A 

0 

2 

5 

0 

aD 

0 

0 

0 

6 

8 

.0 

2 

=D 

0 

5 

0 

0 

0 














SuUboee 


NN Bee oS 


Vipwpn se moclaaes 
ecoooeouc AUNoOanococou 


























Calculation Data—High Bay Units 





0 42 39 38 Al 39 38 40 37 
0 50 48 47 49 AT 46 AT 45 
1 54 53 52 93 02 51 51 50 
1. 58 7 56 56 .09 54 54 53 
1. 61 59 57 58 oT 56 a7 55 


Se OS Ce wh bh 





wre 














SSONS UNOeRNSSONS UbOeS 





























ViPWNN =—=SS le 


-6 
8 
0 
2 
5 
-0 
5 
-0 
0 
0 


25 


TABLE No. 7 (Continued) 
A GUIDE TO THE SELECTION OF REFLECTING EQUIPMENT 














RELATIVE FOOT- 


CANDLES FORA GIVEN| appear. 









LAMP SIZE ANCE OF| piRECT | ,, RE- MAIN- 
GLARE 
ROOM 
On On 
Horizontal | Vertical 





Store and General Utility Enclosing Units 




















8 
Flattened B+ |} B+ A AaB e 
White Glass € 
Enclosing Globe > Excellent Very Very 
90° to 180 °—35% Good Good 


0° to 90°—45% 








9 


Prismatic Glass 
Enclosing Unit 
90° to 180 °—27% 
0° to 90 °—53% 


A B B-— B 


Excellent} Good Very 
Good Good Fair 













Good 



















10 


Enclosed 
Semi-Indirect 
Enameled Bottom 
Etched Top 
Skeleton 
Glass Holder 
90° to 180°—50% 
0° to 90 °—27% 


i 
2 






Excellent Good 















Enclosed 
Semi-Indirect 
Enameled Bottom 
Etched Top 


90° to 180 °—48% 
0° to 90°—32% 


Good 


| Excellent 
Fair 





12 

























Enclosed 
Semi-Indirect A — A B 
Enameled Bottom 
Etched Top Excellent] Excellent Excellent] Good 
(Close Ceiling Only) 


90° to 180 °—53% 
0° to 90 °—22% 


13 







Enclosed 
Semi-Indirect a C ae C a A B =; 
Cased-Glass 
Bottom Very 
Etched Top Fair 







90° to 180°—51% 
0° to 90°—21% 


14 


Enclosed 


Very Very |Excellent| Excellent] Excellent] Excellent 
Fair Fair 
Semi-Indirect S 
Prismatic Glass . 
90° to 180 °—69% 
0° to 90°—17% 










Excellent] Excellent] Excellent| Excellent] Good 










TABLE No. 7 (Continued) 
AND COEFFICIENTS OF UTILIZATION 


PROBABLE AVERAGE ILLUMI- CEILING 
NATION—AS FRACTION 
OF INITIAL ILLUMINATION | 











WALLS 
Clean Average Dirty <r 
; ; ROOM 
Condition | Condition | Condition INDEX 


VERY LIGHT (70%) 


FAIRLY LIGHT (50%) 


FAIRLY DARK (30%) 

















FAIRLY | FAIRLY | VERY | FAIRLY | FAIRLY | VERY | FAIRLY | VERY. 
LIGHT | DARK | DARK | LIGHT | DARK | DARK | DARK | DARK 
(50%) | (30%) | (10%) | (50%) | (30%) | (10%) | (30%) (10%) 


COEFFICIENTS OF UTILIZATION 





Calculation Data—Enclosing U 


























0.6 Es : 14 20 3 , 3 ; 
0.8 27 By .19 25 21 18 .19 EL 
1.0 31 26 23 28 24 21 122 .19 
12 35 30 26 31 27 124 25 22 
1.5 38 33 29 34 30 7 hy 24 

.80 -75 -65 2.0 42 38 33 38 34 31 31 .28 
2.5 46 Al 37 Al 37 34 34 31 
3.0 49 45 40 A3 39 36 36 33 
4.0 53 48 A4 AT 43 40 .38 36 
5.0 55 Sl AT 49 AS 42 40 38 
0.6 28 22 18 26 21 aT “19 "16 
0.8 35 29 25 33 .28 24 26 .23 
1.0 38 33 29 36 32 .28 30 7 
92 43 37 33 40 35 31 33 30 
1.5 46 Al 36 43 38 34 35 33 

.80 -70 -60 2.0 51 46 A2 AT 43 40 40 .38 
2.5 55 51 A6 51 AT 44, AA AQ 
3.0 58 54 50 54 50 AT A6 44 
4.0 62 58 55 57 54 51 50 48 
5.0 65 61 57 60 56 53 52 50 





Calculation D 




















* Semi-indirect and indirec 
are very dark colored. 























ata—Semi-Indirect and Indirect Units 








TABLE No. 7 (Continued) 
A GUIDE TO THE SELECTION OF REFLECTING EQUIPMENT 






RELATIVE FOOT- 
CANDLES FOR A GIVEN 
LAMP SIZE 







APPEAR- 

ANCE OF | DIRECT 
LIGHTED] GLARE 
ROOM 










MAIN- 


LIGHTING UNIT TENANCE 


FLECTED | SHADOWS 
GLARE 












On On 
Horizontal Vertical 


Semi-Indirect and Indirect Lighting Units 





15 


Open 
Semi-Indirect 
Enameled Deflector 
Dense Glass 
Bottom Plate 


90° to 180 °—54% 
0° to 90°—18% 


16 











A | A-— 


Excellent] Very 
Good 


B+ | A- 


Very Very 
Good Good 













Fair 



















qnelpecd ' 

Toni 

aaa direre seed Very Fair | Excellent] Excellent] Excellent Excellent Very 
90° to 180°—64% Fair Fair 


0° to 90°—6% 











17 


Open Indirect 


90° to 180°—80% 
0° to 90°—0% 


Fair 









18 


Recommended in sizes of 100 watts and below. In larger sizes, 


Dense glare and shadows make the open type unit less satisfactory than 
White Glass totally enclosing white units. Its principal application is in such 
Reflector locations as small rooms, closets, stock bin aisles, and other places 


of occasional use where low wattage lamps are suitable. 


Coefficients of Utilization average about the same as for 
Unit No. 9. 


Frosted Lamp 


90° to 180°—12% 
0° to 90°—70% 


Units of this type merely diffuse the light and do not appreciably 
improve the distribution of light as obtained from a bare lamp. 
Flattened units like No. 8 distribute light more efficiently downward 
and are usually to be preferred. Stalactite and spherical globes 
are, however, applicable in waiting rooms, banks and other interiors 
including certain stores where little importance is attached to the 
efficient distribution of light. 


Coefficients of Utilization about 10% lower than values given 
for Unit No. 8. 


aaa The diffusing qualities in both the bowl and the large diameter 
20 reflector render the unit low in brightness with corresponding 
a / ij 
AUT 
paque WY 


19 


Round and 
Stalactite Globes 


90° to 180 °—38% 
0° to 90°—42% 


freedom from glare and sharp shadows. From the standpoint of 
dirt collection it retains the disadvantage of the open bowl. This 


Large O unit is applicable for close ceiling mounting, permitting a wider 


Reflector > 
Open 
Diffusing Bowl 
+4 ° 90°—609/" ee ete of Utilization slightly higher than those given for 

nit No, 8. 












ment, silk, 


AZ 
21 £3 


Enclosing Unit 
Large 
Decorative Shade 
90° to 180°—21% 
0° to 90°—56% 








28 


TABLE No. 7 (Continued) 
AND COEFFICIENT OF UTILIZATION 





PROBABLE AVERAGE ILLUMI- | CEILING VERY LIGHT (70%) FAIRLY LIGHT (50%)  |FAIRLY DARK(30%) 
NATION—AS FRACTION 




































































FAIRLY | FAIRLY | VERY | FAIRLY | FAIRLY | VERY | FAIRLY | VERY 
OF INITIAL ILLUMINATION | Waiig | LIGHT | DARK | DARK | LIGHT | DARK | DARK | DARK | DARK 
(50%) | (0%) | (10%) | (50%) | (30%) | (10%) | (0%) | (10%) 
Clean Average Dirty* ROOM 
‘ondition | Condition | Condition | joey COEFFICIENTS OF UTILIZATION 
0.6 18 a5 13 15 12 10 10 08 
0.8 22 19 17 19 16 14 ‘13 VW 
1.0 "25 ‘99 20 21 ‘18 16 5 13 
1.2 28 "35 ‘29 24 ‘21 19 16 15 
70 | .60 15 31 27 ‘24 26 32 21 17 16 
2.0 34 31 28 28 25 24 20 19 
2.5 37 34 32 30 28 26 "29 2] 
3.0 39 36 34 32 29 28 33 "22 
4.0 37 34 
5.0 40 36 
0.6 14 abl 10 ai 09 07 06 05 
0.8 18 14 ‘13 ‘14 at 10 ‘07 ‘06 
1.0 ‘20 17 15 15 13 VW ‘09 ‘07 
1.2 33 20 17 ‘18 15 13 10 ‘09 
75 | .65 is 26 "39 19 20 17 ‘15 at 10 
2.0 29 26 23 22 19 17 13 12 
25 31 28 26 ‘34 21 20 14 3B 
3.0 34 31 28 "25 "23 "21 ‘15 ‘14 
4.0 37 34 32 ‘27 26 24 ‘17 16 
5.0 39 36 34 30 27 26 18 17 
0.6 15 12 10 ll 09 07 05 04 
0.8 18 ie 13 13 id ‘09 ‘07 ‘06 
1.0 22 19 16 15 13 ah 08 ‘07 
1.2 25 29 ‘19 18 15 13 09 ‘08 
70 | .60 i 27 24 21 20 ‘17 15 10 "09 
2.0 30 27 25 22 19 17 J 10 
2:5 34 31 28 24 29 20 13 ‘12 
3.0 36 30 26 34 "22 14 13 
4.0 "40 34 28 26 24 15 
5.0 37 30 28 26 ‘17 














SPECIAL UNITS FOR COMMERCIAL INTERIORS 





22 m Units of this design have the same character of distribution 
<= as open types, with cover plate serving to exclude the dust 
Enclosed PEE TE and dirt from the lamp and reflecting surfaces of the unit. 


They have the decided advantage from the standpoint of 


ante per paene cleaning accompanied, however, by considerable sacrifice in the 
PehediGlasetlon total light output of the unit. 
90° to 180°—48% Coefficients of Utilization about 20% less than open top 


0° to 90°—10% units of the same design. 





Lanterns of period designs to conform architecturally to 
interiors, are frequently used in public buildings, notably 
churches. Reflectors inside of the ornamental housing increase 
the lighting efficiency and if made of glass may be made to 


23 


Ornamental Lantern 
Art Glass Panels 


Diffusing transmit varying amounts of light to illuminate the side panels. 
Bottom Plate Subject to a variety of design in which distribution ranges 

Internal from direct to totally indirect lighting. 

Reflector Coefficients of Utilization for the type of unit illustrated 





90° to 180°—8% 
0° to 90°—40% 


will average about two-thirds of the values given for Unit No 2. 


Multi-light clusters are in favor as decorative elements in 
public buildings and other monumental interiors. When 
mounted high with a large number of low wattage lamps, the 
result is not unsatisfactory. However, when mounted low, 
the uncontrolled distribution of light and the glare from the 
unshielded sources, spoils what would otherwise be an artistic 
effect. 

Lighting efficiency about 50% lower than same wattage 
in single lamp unit. 


24 


Multiple Light 
Clusters 


Smali Frosted Lamps 









The application of shades to multi-light units will, in 
many instances, raise the over-all effectiveness of the installa- 
tion. On the other hand, the illuminating qualities of large 
decoration designs can be materially improved if the decorative 


25 


Large Main lamp clusters are built around a central large-lamp unit 
Unit either of the indirect type or of dense enclosing glassware. 
Small Decorative A combination of this sort offers a greater flexibility in control 
Lamps of lighting effects, and, in most cases, will allow the illumination 


level to be raised by the use of a larger lamp in the main 
unit at any time if the occasion requires. 





29 


TABLE No. 7 (Continued) 
SPECIAL PURPOSE INDUSTRIAL UNITS 





26 ‘ Generally inferior to RLM Dome with white-bowl lamp 
j because of lower efficiency, sharp shadows, and reflected glare 
Deep Bowl when used above shiny surfaces. Contrary to a common 


impression the light at any angle from a deep bowl steel reflector 
“paper cake is generally less than that from the RLM Standard Dome, 
90° to 180°—0% Coefficients of Utilization average about 15% lower than 


0° to 90°—65% those given for Unit No. 4. 


Highly efficient reflector which, by modification in design, 
can be made to give extensive, broad, or narrow light distribu- 
tion characteristics. With clear lamps it is difficult to avoid 
sharp shadows and reflected glare, and these factors are serious 
handicaps to a more general use of this type of unit, particularly 
at usual mounting heights. White-bowl lamps, properly 


27 


Prismatic Reflector 











Clear Lamp positioned, help these factors, although their use sacrifices, to 
90° to 180 °—20% some extent, accurate control of light distribution as well as 
0° to 90°—74% the efficiency. 


Coefficients of Utilization about 15% higher than those 
given for Unit No. 9. 


This unit like all deep-bowl types has a large shielding angle 

28 to protect against direct glare; it likewise has the disadvantage 

in that it does not protect against reflected glare nor does it 

Mirrored Glass avoid sharp shadows when used with clear lamps. The use of 

Reflector white-bowl lamps lowers the efficiency of the unit about 20%, 

Clear Lamp due iy the light being potted up in the reflector, and, in 
90° to 180°—0% general, are not recommended. 


° oe; Coefficients of Utilization are about 10% lower than those 
OR tO 002 70 given for Unit No. 4. A 
















: This unit has an aluminum reflector inside of a dust tight 
29 ‘ housing. The reflector insert gives a concentrated distribution 
P i and a consequent higher utilization factor in high narrow 
Concentrating ———=4 interiors than would be the case with Unit No. 3. Its lower 
Aluminum Reflector efficiency, compared to Unit No. 7, limits the use of this unit 

Dust-tight Housing to locations where excessive dirt and smoke prevail. 
90° to 180 —0% Coefficients of Utilization average about 20% lower than 

0° to 90°—57% those given for Unit No. 7. 
30 pial Designed for locations where corrosive vapor, inflammable 
pe, gases, or explosive dusts are likely to be encountered. In 
oe cares ar yi moisture laden atmospheres such as canning processes, engine 
popor Bross ae (ial, NN rooms, shower baths; also where gases and vapors from such 
Reflectonith 44) processes as oil refining, varnish making, spray lacquer painting 
Glass Enclosing and the like are present, units of this character are recom- 
Globe mended. See also Unit No, 31. 

90° to 180°—0% Coefficients of Utilization about 10 to 15% lower than 


0° to 90°—68% for an open reflector. 


31 


Vapor-proof Fitting 
ed 

















Applications same as for Unit No, 30; the glass reflector 
is usually not subject to corrosive action and holders are 
obtainable in a variety of metals and compositions to withstand 
corrosion from acid vapors of chemical plants. Recommended 
also in grain elevators, spice, flour and feed mills, in the manu- 
facture of powdered sugar, cornstarch, sulphur, etc., where 
explosive dusts are present. 


Coefficients of Utilization about the same as for Unit No. 9. 


Prismatic 
Enclosing Globe 
90° to 180 °—28% 

0° to 90°—57% 








3 2 Often used in craneways mounted below cranerail to supple- 
ment general pak te system in building up illumination on 
ateral surfaces. sed also to light individual machines where 
es epee pines demand special distribution or direction of light. 
= pecial care must be taken in locating units to avoid glare: in 

Output 74% general, they should be placed high. 





To supplement general lighting where operations require 
high levels of illumination of the order of 50 to 100 foot-candles 
where general lighting of at least 10 foot-candles is provided. 
Local lamps are subject to much handling and for this reason 


33 


Local Lighting Unit 





Se pores glass cover plates are recommended to protect reflecting 
© elac on surface from grease and dirt; construction must be substantial; 


reflectors should not be supported by socket shell. 


25 to 60-watt inside frosted lamps will generally provide 
the level of illumination required. 


Cover Plate 


Output 45-55% 







30 


COLOR QUALITY—APPLICATION OF ARTIFICIAL DAYLIGHT 


A few years ago discussions of artificial daylight were centered about units built on theoretical lines and of 
somewhat uncertain performance. Today, good practical units are being marketed and consequently the field for 
such units has broadened beyond the original conception of limited applications in stores and textile industries. 


The duplication of natural daylight is confined largely to those industrial and commercial applications 
involving accurate color discrimination or color rendition in varying degree, depending upon the specific require- 
ments. Even in this field difficulties arise because the colorist has been accustomed, perhaps through years of 
habit, to a specific daylight quality peculiar to his location. It is practical and expedient, however, to provide 
exact reproductions of daylight for any given requirement with the attendant advantage of constancy and 
24-hour availability. 


Although color quality is accurately specified by color temperature designations, equipments for reproducing 
daylight for working purposes may be grouped roughly into (1) skylight units, (2) sunlight units, and (3) units 
which provide a whiter light than the common types of general lighting equipment, but not so white as those 
listed under (1) and (2). 

















Equipments of this character employ accurately correcting 
filters by means of which it is possible to duplicate the color 
of outdoor daylight. Generally designed for localized lighting 
over counters in stores, for small areas or special operations in 
industrial plants where precision in color identification, grading, 
and other color inspection is required. Illumination of the 
order of 100 foot-candles is desirable for this sort of work. 

Color factories, paint and dye mixing, art studios, chemical 
analysis, dental mechanics, surgery, textile and cigar sorting 
and grading are examples suggesting the application of skylight 
reproducing equipment. 

As compared to unmodified artificial light, from 6 to 8 
times the wattage is required for the same foot-candle values. 


34 


Skylight Quality 


Special Color 
Filter 


Clear Lamp 





the inside modify the light from a lamp to approximate the 
color of direct sunlight at noon. Their applications are to 
some extent the same as skylight units, the actual choice 
depending on specific requirements; in general, noon sunlight 
equipment is used for less exacting color discrimination. For 
example, ink and dye mixing, and inspection may be done 
locally under skylight quality, and a general system of noon 
sunlight equipment may be installed in certain rooms or over 
small areas restricted to manufacturing operations requiring 
clear color rendition—such, for example, as lithographing 
processes, color printing and the like. 


A\\ 
so aé 


ail 





35 M_|\\ 


Sunlight Quality 


Reflector and 
Color Correcting 
Globe 


Clear Lamp 


As compared to unmodified artificial light, from 2 to 3 


Enclosing globes of special crystal blue glass frosted on 
times the wattage is required for the same foot-candle values. 





“Daylight” lamps, emit a whiter light which is but a partial 
step toward daylight whiteness. In many instances of color 
rendition, their use gives sufficient color correction to be of 
considerable advantage over the warmer tones of unmodified 
light. For example, they are widely used in stores and show 
windows to improve the display of merchandise. Again the 
light blends well with natural daylight; in fact in many cases 
it is about the same color as the daylight which one gets 


36 


Ordinary 2 5 fj h 1 4 
Equipment indoors taking into account the prevalence of warm tones in 
window shades. walls and hangings; for this reason the use 
Blue Bulb of daylight lamps in offices and many other places will be found 


to correct an unsatisfactory mixture of ordinary artificial light 
and inadequate daylight. 

The next larger size of lamp will be required to produce 
approximately the foot-candle level as computed for a clear 
lamp of a given size. They are used in all common types 
of equipment. 


Daylight Lamps 


Enclosing globes with slight bluish ingredient do not 
appreciably modify the color quality of illumination for 
utilitarian purposes, but have a considerable field of applica- 
tion by virtue of their whiter appearance. Such equipment is 
correct. for the yellowish tone usually noticeable with ordinary 
opal glassware. These usually give far less color correction 
than Mazpa Daylight lamps. The units are very pleasing, 


37 


Color Modifying 


Globes appear white and clean, and are often more satisfactory than 
Cl r units of yellowish tone, particularly when supplementing 
eis TEA natural daylight. The spectral quality of illumination is 





usually not far from that of a clear bulb Mazp, C lamp. 


Coefficients of Utilization will be about 10% to 30% less 


Lamps with blue bulbs, commercially known as Mazpa 
than the values given for Unit No. 8. 





31 


Lamp Size—Lumen Output Required 


4. 


TABLE 8—COMPUTED ILLUMINATION VALUES 


In this table the actual foot-candles have been worked out for man 


initial 


y different 


ice to be 70 per cent of the 


the average foot-candles 






























































In serv 











COEFFICIENT OF UTILIZATION 





















































a |e 
eo Ae 
bal 5 
1) 
g§ o |S 
5-5 AN a 
ne a |e 
=| 
| £3 4 
0] com) 
gE gi § § 
© .Aa8 
a= we 
O om <A 


comes “ONO wWOVPN ooann Omon Anwr AAAS Ver Ho ad OMA AMOO CANS ~eetr~e COnmAN 
See AS ERGs Rea SUN | wan |toda |reaoe [emer | eSoes waste |ranr | ocowm | mans 
man of eNO Seo ee mn ne | rm AN Sm N eetN miN Seon oe | =n 








om Ot wore aooRm WOMON AOA S wwnuno rorwn connn AFOOCON Con r ANAS NoOr~w FINO 
aA ae ealar) aan aN aN an aan aren aan ae C 








recor See oD wWwmon NOON DOANN NAocow => ANON wowr ANDO wowrvo Othe reno oncom 
SHoHt | SSnd |uracn Tce a co RECT: [et Cee CN a Sore Rai somnn | onnr |oodte | MOND | wrndh 
oe orl eel Ce | Oe | mN ee eet ON en | ee ae 





determined, 


AQIS U Omran KIN ronmn Fores Ataeeo racow SAN nero AON SnuN AMON Caan 
wore IN HOw monn | Feds tren o Mooer | MowWN wnaANS FON | HMO Cama | mono | Frown 
asec Lo} ein). Lo | aN ie 
CMON | ataw rere no MADN | CODW in co SN ANtS | Omot ail | ee wom | co LNLD AWA 
mowew wn COLn oD sear SREND | POMS MINSCO | NAS FON Ss eo) moo | Mana trow | t#oam 
aN mn ns | ae ee C eo oe _ 









































Smenm | Ooon | nouns AAnn | Corr ANBWO }]|onos Anew | reretr | morta onon NM-NDA | reono 
wens | FreAn | FreND Mmonrr | moore CUDA | HCO ODS sreHo | moot | Monn wmeaE | HOD | MINOM 
mN mn ae ac Cm = ee ae 














meme pa HO | RAE | SRA | Nine | CONS Sey SER [AAS PSeme | MAD | OABN | IAMS 
aenae|sone |mork awwow | muadt | ator Sra | aso | muan mine | ROAM | mice | ord 
aN [on ama ae Llama cal Cl Coal eo 
Shee |RaaS | SOSs | FANN [awonm | waren HOSE [OMA | Smma [rane SADA | HAOH [Ors 
occ moor |anow e018 Ost ooo oD age mood | moa | mmo |agro | HOO COLD tm HFOS 

















—-—— 

OHO’ metres | CAD COON | ONOC Are | MANS one Oran | tors NNO | CHRO | HRAN 

MmNSO | MINA cmc CUSTiCoIGN Ate NS mina | mince NERS | NAODN MNrKA | MAOS | AMNOD 
oe 

















izes of lamps can be obtained directly 


LUMEN OUTPUT REQUIRED 
e and the coefficient of utilization 
COEFFICIENT OF UTILIZATION 
FOOT-CANDLES 











SND | ARINAN | OMAR | FONN AEE | one | ances or ore Aaa |S RON | MONS | RAAN | MOMS 
COL AS NPFOM (ASN iS bore NMOS | AMA | Noo NEKO | NAOD | NMS MAOS | AANA | NMC 








DEMS | MWANCHD | MAH OFS | OMAN ODN | CONN Mana | Kran | ann OMAO | SrMM | ANON 
aeom |ANAEeR | NMOS QoS AMA | AAW SS ES NAFOD | NMS | RK oMwe APFOHD | AMINO | ANSE 
= 





we ot | AreS | eK teH Amoe | ONAN WooM |nANSo | orerr DOMAN | CHOW sown |AmMmom | ano 
Cl SUES AMCS | AMOD | AmMMe aan | ANSE | ANBOD Nene | emer | AANHO NANO | AMA | AANAHO 
Qi-es | oot | acne raAnmo|ounm SOND | Keon Hares eoww DEAD | ANAY | HONS rore 
AROS AMON | eens eNO | RANE HNO |AMNS | AMMe amdto | Renan | ANSE AaHOoO | AN WH 



































16 18 | .20 | .22| (25 | .28 | .32 | .36 | .40 | .45| .50 | .55 | .60 | .65 | .70 


duced by various s 


-14 | 


has been mad 








LAMP SIZE 
TABLE 8—COMPUTED ILLUMINATION VALUES 


table. 
Size of Lamp 








After the layout 
e foot-candles pro 
from this 
Lamp 


th 
































| | a | | cs a | | ——— 
OOOO Oe | oo ————SS OO | wl 
coooleocoecoiococoeo ccooci;eocesc cccoo |;eoeeo coco loosce |oooeo cooolecesoiooceo 
eeseissoo!iseoce esesoi;ooeceo ecess;essoes;ecosce eesselesoqoliococee2 escoo |;oooeo 
AmMne | AMMO | AMNS Gissine | gimme | Nu MHEO|MNODS|MNAS mnrneaso|maceo|;wece nooo 
OIDAH | MINA | MAS IDA | MIAH ODA | WAS | WAS DAS | WAG | ARMAS AtAaM | ata 

e Lal e Cl Ll e aN mN aN mN Ca orl aN mNO 


ee a ed reed 




















Watts! Lumens 


















































200 
220 








LAMP SIZE— LUMEN OUTPUT REQUIRED 


Formulas for Computing Lamp Size 


After the outlets have been located on the plan, the size of 
lamp to be used may be determined by the following calculation: 


(A) Area in Square F. eet _ Total Floor Area in Square Feet 
per Outlet Number of Outlets 


Lamp Lumens 


(BMH ec dined pene Foot-Candles 


Ss Foot Coefficient Probable Average Illumination 
So madden of >< in Per Cent of Initial 
Utilization Illumination 


Lamp Lumens Area in Square Feet Lamp Lumens Required 
(C) Required per = per Outlet x per Square Foot 
Outlet (From A) (From B) 


Having determined the lamp lumens required per outlet by the 
above calculations, the wattage of Mazpa lamps to be used may 
be found by reference to Table 9, below, which lists the lumen 
output rating for each size of Mazpa clear and Mazpa Daylight 
lamps. Locate in this table the size of lamp of the desired type 
which most nearly meets the requirements of lumen output. When 
the lamp lumens required fall nearly midway between two sizes, 
it will usually be found best to choose the larger size. 


TABLE 9—LUMEN OUTPUT OF MULTIPLE MAZDA LAMPS 


Subject to change without notice 























110-115-120 Volt 110-115-120 Volt 220-230-240-250 Volt 
Standard Lighting Service | Standard Lighting Service Service 
Clear Lamps Mazpa Daylight Lamps Clear Lamps 
Size of Size of Size of 
Lamp in Lumen Lamp in Lumen Lamp in Lumen 
Watts Output Watts Output Watts Output 
100 1350 100 900 100 1040 
150 2300 150 1500 se pene ee ae 
200 3200 200 2100 200 2700 
300 5300 300 3500 300 4300 
500 9500 200 6200 500 8100 
750 14800 oe we ee See 750 13000 
1000 21000 t Saas HN pie een 1000 18200 
1500 33000 sey eeu as sae 1500 27300 











34 


LIST OF MANUFACTURERS 


MANUFACTURER TRADE NAME OF UNIT 
Unit No. 1 (60 to 1500 watts) 


*Benjamin Electric Manufacturing Co. ze 
*Tvanhoe Division of the Miller Co. -  - 
pe ceunenonee eee ae Manufacturing Co. 
*Wheeler Manufacturing Co. - = = 
*National Screw and Manufacturing Co. - RLM Standard Dome 
Overbagh and Ayres Manufacturing Co. - 
Quadrangle Manufacturing Co. - -~— - 
Central States G. E. Supply Co.-  -~— - 


Unit No. 2 (150 to 500 watts) 
Manufacturers marked (*) under Unit No.1 -  Glassteel Diffuser 
Unit No. 3 (60 to 500 watts) 


Ivanhoe Division of the Miller Co. - -~ - 
Benjamin Electric Manufacturing Co. -  - }RLM Dust-tight 
Wheeler Reflector Co. - - -~ - = - 


Unit No. 4 (60 to 1500 watts) 


Same as for Unit No.1- - - -  -  - RLM Standard Dome 
Unit No. 5 (500 to 1500 watts) 
Holophane Glass Co. - - - -  -  -  Holophane 


Unit No. 6. (750 to 1500 watts) 
Pittsburgh Reflector Co. 
Curtis Lighting, Inc. - 

Unit No. 7 (750 to 1500 watts) 
Ivanhoe Division of the Miller Co. 

Unit No. 8 (100 to 500 watts) 


Flattened globes of this character are made by most lighting glassware 
manufacturers and marketed under various trade names. The best quality 
will have a light output of about 80% and yet be sufficiently diffusing that 
the globe is of uniform brightness. The-minimum diameter of globe for a 
given lamp wattage is as follows: 


Permaflector 
Big Boy 


Industrial Flood 


US O0nw atts eee 12-inch 300 watts. ........ 16-inch 
ANOLE, oo Goood 14-inch SOO kwatts eee 18-inch 
Unit No. 9 (100 to 500 watts) 
Holophane Glass Co. - - - = 7 - RR (Reflector-Refractor) 


Unit No. 10 (100 to 500 watts) 
Goodrich Electric Co. - - - - - - 
Beardslee Chandelier Co. -~— - = 4 - Clear Top 
Henkel and Best Co. - -— - -  - - 

Unit No. 11 (100 to 500 watts) 


Graybar Electric Co.,Inc. - - - - - 99 Reflex 
Unit No. 12 (100 to 300 watts) 

Wakefield Brass Co. - - - -  -. - Red Spot Office Unit 
Unit No. 13 (150 to 500 watts) 

Ivanhoe Division of the Miller Co. - - -  Keldon 
Unit No. 14 (100 to 500 watts) 

Holophane Glass Co. =< - - - - - Filterlite 
Unit No. 15 (100 to 1500 watts) 

Duplexalite Division of the Miller Co. - -  Duplexalite 
Unit No. 16 (200 to 500 watts) 

Curtis Lighting, Inc. - - - - - Winall 


35 


LIST OF MANUFACTURERS 


MANUFACTURER TRADE NAME OF UNIT 
Unit No. 17 (100 to 1500 watts) 
Curtis Lighting, Inc. - - - - - - £=X-Ray 


Unit No. 18 (25 to 150 watts) 
Made by most Lighting Glassware Manufacturers. 
Unit No. 19 (60 to 1000 watts) 
Made by most Lighting Glassware Manufacturers. 
Unit No. 20 (100 to 500 watts) 
Planetlite Company, IGG - - - - -  Planetlite 
Edwin F. Guth - - -  - = = Brascolite 
Unit No. 21 (100 to 500 watts) 


Art stores and studios, in general, make a specialty of executing designs in 
silk, parchment, and other suitable shade materials. 


Unit No. 22 (100 to 500 watts) 
The Duplexalite Division of the Miller Company Duplexalite 
Units Nos. 23, 24, 25 


Specifically designed ornamental equipments will be made up according to 
specification by a considerable number of lighting fixture manufacturers. 


Unit No. 26 (25 to 1500 watts) 


Same as list for Unit No. 1 - -  - = Deep Bowl Steel 
Unit No. 27 (100 to 500 watts) 
Holophane Glass Co. - - - -  -  -  Holophane Prismatic 


Unit No. 28 (100 to 500 watts) 
Curtis Lighting, Inc. - - - - = - 
Unit No. 29 (200 to 500 watts) 
Ivanhoe Division of the Miller Co. 
Unit No. 30 (60 to 500 watts) 


Benjamin Electric Manufacturing Co. -  - 
Ivanhoe Division of the Miller es - -  -  ¢Vapor Proof 
Wheeler Reflector Co. - — - Stes SS 


Unit No. 31 (40 to 200 watts) 


Industrial Floodlight 


Holophane Glass Co. - - - -  -  - Vapor Proof 
Unit No. 32 (25 to 1500 watts) 
Same as list for Unit No. 1 - -  -  - Angle Type 


Unit No. 33 (10 to 50 watts) 
Ivanhoe Division of the Miller Co. - -~ - 
Benjamin Electric Manufacturing Co. - - 


Unit No. 34 (150 to 1000 watts and in multiple units) 


MacBeth Daylighting Co. - - - =  MacBeth 

Ivanhoe Division of the Miller Ce eee rutine 
Unit No. 35 (200 to 1000 watts) 

Ivanhoe Division of the Miller Co. - - - Noon Sunlight 
Unit No. 36 (60 to 500 watts) 

Mazpa Lamp Manufacturers - - - - Mazpa Daylight Lamp 
Unit No. 37 (100 to 750 watts) 

Gleason-Tiebout Glass Co. - - - - -  Celestialite Glass 


36 


3 
| BULLETINS OF THE NATIONAL LAMP WORKS 


b| 

~7D—Fundamentals of Illumination 
This bulletin presents the principles of light—its measurement, its control 
and distribution—together with essentials of illuminatien design—60 vages. 
Illumination Terms, a supplement to Bulletin 7D, is a dictionary of light- 
ing terms.—56 pages. 


33C—Picture Projection with Mazpa Lamps 
' A practical discussion of the principles of Mazpa lamp projection and their 
if, application.—54 pages. 
41D—MIlumination Design Data for Commercial and Industrial Interiors 
This bulletin presents a simple method of illumination design adapted to 
' general lighting systems where standard equipment is to be used. Charts and 
4 tables simplify the method and make for accuracy in the design.—36 pages. 


* 42B—Factory Lighting Designs : 
Ready-made illumination plans for the more common bay sizes found in 
industrial interiors are presented in this bulletin—48 pages. 


44A—Incandescent Lamp Temperatures 
Data on operating temperatures of lamps, wiring parts, and fixtures.— 
36 pages. 

45A—Lighting Designs for Stores 
Presents lighting recipes for a number of typical store interiors, with designs 
and notes on lighting of the display windows——48 pages. 

A46A—Street Lighting Designs 5 
Simple recipes are given for the lighting of business, thoroughfare, and 
residence streets for cities of various sizes.—20 pages. 


“47A—Home Lighting Fundamentals 
A practical guide for lighting the home, replete with sketches illustrating 
the use of various types of lighting fixtures to obtain desirable lighting effecis 
Al in the different. rooms.—32 ‘pages. 


50A—Electrical Advertising—lIts Forms, Characteristics, and Design 
This bulletin contains a discussion of the requirements, characteristics, and 
adaptabilities of the principal forms of electrical advertising, and simple 
approximate rules to guide the sign user and builder.—48 pages. 


51—Night Lighting for Outdoor Sports 
This bulletin discusses the various types-of equipment and gives compre- 
hensive lighting plans for tennis, volley ball, race tracks, bathing beaches, 
and a number of other common outdoor recreations.—24 pages. 


' 52—Photographic Lighting with Mazpa Lamps 
Analyzes the requirements, describes the equipment, and illustrates the results 
obtained with Mazpa lamps in portrait and commercial photography.—64 
pages. 
53—Farm Lighting 

Pertinent to the general interest and widespread activities in farm electrifica- 
tion, this bulletin presents lighting recommendations which are practical and 
satisfactory for the various farm buildings and the farm home.—36 pages. 


54—Floodlighting ‘ 
Presents a comprehensive design procedure together with suggestions on 
floodlighting effects, equipment, and equipment location—48 pages. 


Many other publications are available, dealing with specific phases of lighting 
—schools, hotels, stages, printing plants, cotton mills, automobile headlighting, 
Christmas lighting, maintenance, airway roof signs, etc. When requesting pub- 
lications, please state the subjects in which you are interested. 





THE SALES ORGANIZATION OF THE NATIONAL 
LAMP WORKS OF GENERAL ELECTRIC CO, 


ALLEGHENY DIVISION 
ATLANTIC-FEDERAL DIVISION 
BUCKEYE DIVISION . 
CONTINENTAL DIVISION 
EMPIRE DIVISION 

MICHIGAN DIVISION 
MIDLAND-FEDERAL DIVISION 


MISSISSIPPI YALLEY DIVISION . 


NEW ENGLAND DIVISION 
NORTHERN DIVISION 
PACIFIC DIVISION 
SOUTHERN DIVISION 
SOUTHWESTERN DIVISION 
SUNBEAM DIVISION. 
SUNBEAM DIVISION . 


PITTSBURGH, PA. 
NEW YORK, N. Y. 
CLEVELAND, OHIO 

- PHILADELPHIA, PA. 
. BUFFALO, N. Y. 

. DETROIT, MICH. 
CHICAGO, ILL. 

ST. LOUIS, MO. 

. BOSTON, MASS. 
MINNEAPOLIS, MINN. 
OAKLAND, CALIF. 
ATLANTA, GA. 
KANSAS CITY, MO. 
NEW YORK. N. Y. 
CHICAGO, ILL. 


AT EACH OF THESE OFFICES A LIGHTING 
ENGINEER IS AT YOUR SERVICE 


{ 


\ y 


i 


ENGINEERING DEPARTMENT 


NATIONAL LAMP WORKS 


OF GENERAL ELECTRIC CO. @ 
NELA PARK, CLEVELAND 





